Development of a quantitative chromatographic method for the determination of Imatinib and its main metabolite in human plasma

Abstract: The objective of this master thesis was to develop an analytical method for the quantification of the cancer drug Imatinib and its main metabolite CGP74588 in plasma. Imatinib is used in the treatment of chronic myeloid leukemia and gastrointestinal stroma tumors. A quantitative analytical method was developed where reversed-phase columns with different stationary phases were studied and the sensitivity was tested with both UV detectors and a mass spectrometric detection. Since the substances were measured in plasma a solid-phase extraction was developed to purify the samples before analysis. The column chosen for the separation was the Max-RP C12 column (100 x 3 mm, 4 μm particle size) manufactured by Phenomenex with a gradient mobile phase with 1% formic acid in methanol and water. The gradient was as follows; 0 min 15:85, 7 min 60:40, 9 min 60:40 with a total runtime of 13.5 min. The internal standard chosen was Opipramol. Mass spectrometric detection using a sonic spray ionization interface in positive mode proved to be about as sensitive as UV detection at 261 nm. The generated (M+H+)+ ions were isolated and fragmented with the use of three mass spectrometric methods; one for Imatinib (transition 494 —› 394), one for CGP74588 (transition 480 —› 394) and one for Opipramol (transition 364 —› 171). For the purification of the plasma samples an Oasis HLB solid-phase extraction cartridge was selected and the recoveries were close to 100%. The developed method was partially validated and showed coefficients of variation (CV) for intra-and inter-day precision between 0.4 and 5.4% with UV detection. The validation results for the mass spectrometer were inconclusive.